I also have a small GUI built with Flask so I can control Fwd/Back, turn and Stop. This seems to work at first; I can move in reverse (throttle = -0.5) and turn right and left. I can also do Stop from either of those directions.

However, when I go to forward (throttle = 1 on both motors), if I then try to stop (or reverse or turn), the motors stop responding (stuck in forward) and I get this error from my gui;File "/usr/local/lib/python3.7/dist-packages/Adafruit_PureIO/smbus.py", line 308, in write_bytes self._device.write(buf)OSError: [Errno 5] Input/output error

There's a lot more of the error traceback, but those are the last two lines. The only way to stop the motors is to hit the Hat reset button.

I have updated the seesaw firmware. Any clues what could be going on here?

I'm wondering if it's due to electrical noise generated by the motors. You can try soldering a ceramic or disc 0.1uF capacitor between the motor tabs (on the motor itself!) this will reduce noise that could be feeding back into the circuit.

Thanks for the suggestion. Yes, I tried throttle -1, and the motors seem to stall out and then give the same error. The reason I bought the Crickit Hat was i thought it handled all of the motor drive needs. I will see if I can track down some capacitors.

It does give you the drive capacity, but motors are noisy things. Another thought... is your battery powerful enough to supply both motors running at full speed? Noise or a power brownout might be crashing the seesaw chip.

Dave, thanks for that suggestion. I am currently looking for a more powerful battery pack, to see if that solves the issue. I am now seeing a flashing red led (right next to the on/off switch) on the Crickit hat. Do you know what that means? I measured the batteries at 6v, but not sure where to take a measurement on the board under load to see true voltage.